In recent years, as a technique for improving the frequency utilization efficiency and/or the like, a heterogeneous network has been under study, in which a macro cell being a base station (may be referred to as “eNB”) having high transmission power and a small cell being a base station having low transmission power are disposed in a mixed manner.
Splitting between a Control plane (hereinafter, referred to as “C-Plane”) and a data plane (User plane) (hereinafter, referred to as “U-Plane”) (C/U split) in a communication system forming the heterogeneous network has been proposed. More specifically, during C/U split, the macro cell maintains connectivity by mobility management using the C-Plane while the small cell handles the U-Plane using a wideband frequency, thereby providing high throughput (e.g., see Non-Patent Literature (hereinafter, referred to as “NPL”) 1).
Furthermore, the macro cell determines whether handover (HO) of a terminal to another macro cell is required or not on the basis of reception quality information (Measurement Report) provided as a feedback from the terminal (may be referred to as a mobile station (MS) or user equipment (UE)).